There are several types of medical devices that use electrical stimulation to stimulate nerve, muscle or other tissue fibers in a recipient. Sometimes, the electrical stimulation is applied to compensate for a deficiency in the recipient. For example, electrically stimulating hearing prostheses, such as cochlear implants, have been developed to evoke a hearing percept in a recipient thereof.
In particular cochlear implants (also referred to as cochlear devices, cochlear prosthetic devices, cochlear implants, and the like; simply “cochlear implants” herein) apply one or more stimulating signals to the cochlea of a recipient to stimulate hearing.
Cochlear implants can include a sound input device that receives incoming sound, and a sound processor that converts selected portions or all of the portions of the incoming sound into corresponding stimulating signals based on an implemented sound encoding strategy. The sound processor transmits the stimulating signals along an electrode array implanted within or adjacent to the cochlea of the recipient.
Cochlear implants exploit the tonotopic organization of the cochlea by mapping audio energy in specific frequency bands to deliver stimulation at corresponding locations along the spiral array of auditory nerve fibers. To achieve this, the processing channels of the sound processor; that is, specific frequency bands with their associated signal processing paths, are mapped to a set of one or more electrode contacts of the electrode array to stimulate a desired nerve fiber or nerve region of the cochlea. Such sets of one or more electrode contacts are referred to herein as “electrode channels” or, more simply, “channels.”
Another example of an electrically stimulating hearing prosthesis is an auditory brainstem implant which delivers electrical stimulation to the auditory brainstem nuclei of a recipient to evoke a hearing percept.
Some electrically stimulating prostheses deliver stimulation via a single electrode contact (mono-polar stimulation), while other electrically stimulating prostheses apply stimulation via a plurality of electrode contacts (multi-polar stimulation).